Women have been heading up congressional offices dating back to the 1940s, but that “assistant” position looked very different from today’s chief of staff post.

The 1946 Legislative Reorganization Act created the title of administrative assistant, which evolved into chief of staff. In 1947, there were about six female administrative assistants in the Senate, according to Senate Historian Betty K. Koed.

The number didn’t hit double digits until the mid-1970s. Around 1984, the title “chief of staff” started to appear in the phone directory.

“At the time a lot of people still used the AA, administrative assistant, title. I think one of the reasons that changed [was] when women were … using that title, people thought they were secretaries,” she said.

Keefe, who now serves in the same position for New Hampshire Democratic Sen. Jeanne Shaheen, recalled wanting to be addressed as chief of staff because, as she put it, “I don’t want people from the outside world calling and thinking I’m taking dictation in here.”

DeLauro herself is no stranger to the role. When Sen. Christopher J. Dodd first came to Congress in 1981, he brought his campaign manager, DeLauro, to serve as chief.

“It was a daunting experience, and at that time, I think there may have been five of us women,” she said. Democratic Sens. Patrick J. Leahy of Vermont and Bill Bradley of New Jersey also had female chiefs, she recalled.

By 1986, the number was roughly 16, Koed said. It grew to 20 by the 1990s, and to 25 by the 2000s. There were 27 in 2014 and 32 today.

Along the way, other trailblazing careers took shape. Betsy Wright Hawkings became one of the youngest female chiefs in 1990, leading Connecticut GOP Rep. Christopher Shays’ office, and Kathy Gille became one of the first women to supervise a whip operation in the House in 1991 when her boss, Michigan Democrat David E. Bonior, became House majority whip. (Hawkings is married to Roll Call senior editor David Hawkings.)

“It was a steep climb,” said DeLauro, who served almost eight years as chief. “In the issue of being taken seriously, as a female chief of staff, you have the right mix of knowing when to be tough [and] knowing when to back off. I think women always have a tougher road to go down in these areas.”

While DeLauro recalled being treated differently sometimes because of her gender, she also had great male allies. One was her boss, who she said had a lot of confidence in her and allowed her to voice her opinion. Another was former Sen. Ted Kaufman, then chief of staff to fellow Delaware Democrat Joseph R. Biden Jr. when he served in the Senate.

“You can’t be faint of heart. It’s like being a member of Congress. You’re not going to get a leg up because you happen to be female. You have to be able to do the job,” DeLauro said.

She said Keefe, for example, is someone who “doesn’t mince words.”

“There are instances … where you’re in a meeting with a group and you’re with a younger, more junior male member of your staff and they’re addressing the male member of your staff,” Keefe said. “It happens. It’s an unconscious bias.”

Keefe has worked for Shaheen since 2009 and chairs the Democratic chiefs of staff weekly meeting. Her Republican counterpart is another woman, Lisa Goeas from Iowa Sen. Joni Ernst’s office.

Keefe also co-founded the annual Women on the Hill dinner for the Democratic Senatorial Campaign Committee, which had its sixth dinner earlier this month. The dinner started after the DSCC hosted a Senate chiefs event that only featured men.

“A bunch of women from downtown who were invited emailed myself and emailed some other women chiefs at the time and said, ‘Hey, what the heck? Why aren’t you guys at this?’” Keefe said.